利用python字典，编写一个简单完整的用户登陆界面

以下是一个简单的用户登录界面，使用Python字典存储用户名和密码：

# 定义用户字典，存储用户名和密码
users = {
    "user1": "password1",
    "user2": "password2",
    "user3": "password3"
}

# 欢迎界面
print("Welcome to Login System")

# 循环等待用户输入用户名和密码
while True:
    # 获取用户输入的用户名和密码
    username = input("Please enter your username: ")
    password = input("Please enter your password: ")

    # 检查用户名和密码是否匹配
    if username in users and users[username] == password:
        print("Login successful!")
        break  # 跳出循环，登录成功
    else:
        print("Invalid username or password, please try again.")

运行代码后，将会看到如下输出：

Welcome to Login System
Please enter your username: user1
Please enter your password: password1
Login successful!

如果输入错误的用户名或密码，则会看到如下输出：

Welcome to Login System
Please enter your username: user1
Please enter your password: wrong_password
Invalid username or password, please try again.
Please enter your username: user2
Please enter your password: password2
Login successful!